Jargon Analyzed
Well, The list can be huge and I'll gradually keep adding to it, the older terms as well as the new ones that appear, as the technology moves ahead. Right now, I'll concentrate on those which should help you in selecting a new camera.
Censor / CCD / CMOS / Megapixels : Please read this post elsewhere on the site.
ISO: Denotes sensitivity of the censor to light, most commonly used value being 100. Increasing the sensitivity affects exposure setting by allowing the censor to gather more light for the same shutter speed and aperture opening. Thus, pictures shot in less lighted conditions with high ISO setting expose the image better. However, there is an increase in noise with the increase in ISO value. ISO values beyond 400 may hardly be usable in compact cameras. Therefore, you can safely ignore astronomical values like ISO 1600. They have rarely done anyone any good.
Auto White Balance: We always see 'white' as 'white' and there doesn't seem to be anything great about it, right? As a matter of fact, the white as we see in daylight, cloudy conditions, morning/dusk, night, under artificial lighting and other such situations, are all significantly different sum total of colours. To simplify the matter, our brain has memorized certain values for 'white' and every time we come across 'white' we see it as 'white' should be. Cameras are not so lucky. They are factually exposed to different shades of white (i.e., white with colour casts of red, gree or blue) in all their glory. The trouble is, they calculate other shades with a reference to the 'white', complete with the predominance of a particular channel. Auto White balance provides the camera the data of the possible hue that white may assume in a given lighting condition. On the other hand, if the manual white balance adjustment is featured in the camera, you can meter it to certain reference value or maybe, by using a standard 18% gray card. Usually, the feature does the job.
Optical Zoom: The ability of the lens to change the focal length. Useful in filling the view with objects at a distance. If the starting focal length is 35mm and the camera can zoom to 105mm, it has an optical zoom factor of 3X. Please read this post elsewhere on the site.
Digital Zoom: A misguiding, non-existent phenomenon. Please read this post elsewhere on the site.
Optical Image Stabilization (VR / IS): Nikon calls it VR (Vibration Reduction) and Canon calls it IS (Image Stabilization). When you frame an image you want to capture, it should remain unchanged while the shutter opens and shuts (remember, its a still image). Its normally not much of a problem if the censor speed is set to 1/250th of a second or higher. However, depending on the ambient light, the shutter speed may easily dip below 1/60th of a second or even to 1 full second. What happens then? Since its very difficult to keep your hands perfectly frozen for such an extended period, the camera shakes and the still image which is in the process of being imprinted on the censor, shifts with the movement. You end up with a blurred, unfocussed image in the process. Recently, the camera manufacturers have started introducing an optical element in the lens which moves in the opposite direction of the camera shake. Its an extremely useful feature and allows you take pictures in comparatively less ambient light. A must have.
Manual Mode: In the Automatic Mode, the camera determines the exposure and sets certain values of aperture and shutter speed to suit it. Manual mode allows you to tinker various parameters for the exposure. Its an excellent feature if you intend to advance your art.
Red-Eye Reduction: When the flash is fired all too suddenly, which is what it often is, pupils fail to contract and the intense lights collects the colour of blood cells from the choroids and the retina of the eye. The cameras counter this by emitting an invisible pre-flash before the actual firing. Some cameras eliminate the red-eye by in-camera processing after the picture has been recorded.
Aperture Priority: For a given exposure, the camera will allow to set the aperture value and find the corresponding shutter speed. The feature can be used to change the depth of field, i.e., area in focus. For instance, in a portrait shot, the background can be thrown out of focus by choosing a lower aperture value. Unfortunately, the feature is less effective in a compact camera compared to a DSLR because of the miniature size of the lens.
Shutter Priority: For a given exposure, the camera will allow to set the shutter speed and find the corresponding aperture value. In order to capture a still image of a moving object, a higher shutter speed is required. This feature is useful.
Scene Modes: These are a set of predetermined combinations of aperture and shutter-speed values for certain situations. For instance, the 'Sports' mode is likely to have high shutter speed, the 'Landscape' mode is likely to have a closed aperture value, the 'Portrait' mode may have an open aperture and so on and so forth. Quite helpful.
Face Detection / Face Priority: Normally, when you point your camera at the subject, be it a person, an object, a landscape or whatever, the metering system takes a reading from the entire frame. If, however, your subject is a person or a group of people, the Face Detection / Face Priority feature identifies the face / faces and exposes them perfectly by allotting less priority to the surroundings. Quite helpful.
D-lighting: "Brightens up a subject that has been underexposed due to backlighting or insufficient flash illumination." Quite helpful.